Boat



P. DE MICELIS 2,337,376

BOAT

Filed April 3.9. 1941 2 Sheets-Sheet IN VENTOR.

PE ER DE MICHELIS wag ATTORNEY.

Patented Dec. 21, 1943 iJNlTED STATES PATENT OFFICE BOAT Peter De Michelis, San Francisco, Ualif.

Application April 19, 1941, Serial No. 389,374

3 Claims.

My invention relates to Water craft, and more particularly to surface boats adapted for high speed purposes such as torpedo boats.

It is among the objects of my invention to provide a boat which travels above the water with a minimum of contact with the water surface, thereby largely eliminating the water to hull friction and enabiing the craft to develop very high speeds.

Another object is to provide a hull having a longitudinal section of airfoil shape, utilizing the lift of the air stream to aid in maintaining a minimum water contact.

Another object is to provide an improved bottom construction for high speed surface craft.

Still another object is to provide an improved propulsion means for a boat of the character described.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of my invention. It is to be understood that I do not limit myself to this disclosure of species of my invention, as I may adopt variant embodiments thereof within thescope of the claims.

Referring to the drawings:

Figure 1 is a side elevation of a boat embodying the improvements of my invention.

Figures 2 to 5, inclusive, are cross sectional outline views taken in planes. indicated by the correspondingly numbered section lines in Figure 1 Figure 6 is a fragmentary top vievnpartly in section, showing the propulsion units and steering mechanism.

In terms of broad inclusion, my boat comprises a hull having a longitudinal section of airfoil shape. The bottom of the hull is stepped, and the offset bottom areas are of improved design. Improved propulsion means are also provided for the boat.

In greater detail, and referring to the drawings, my boat comprises a hull having a top 2, sides 3 and a bottom l. A suitable skin of planking or metal is provided on the top as well as the sides and bottom so that the boat is wholly enclosed. A stream lined cabin 6 provides for visibility from the operators compartment; and openings with suitable closures are provided in the top for ingress and egress, otherwise the smoothly curved top surface is uninterrupted. The hull interior may be of any suitable construction. In this connection I prefer to provide a plurality of rigid reinforcing webs 1 running the length of the hull and extending the full distance between the top and bottom. These webs, coextensive with the longitudinal section of the hull, form structural beams which insure against breaking in the middle as speedboats are apt to do under the severe pounding they take.

Important features of my invention lie in the shape of the hull, both as to its general contour and the particular shape of its bottom. The boat is designed primarily for speed. Since the resistance in air is less than that in water, my boat is designed to travel as far out of the water as possible. In order to take advantage of the lifting force of an air stream the boat has the general contour of an airfoil; in other words, the longitudinal section of the hull is of airfoil shape. This not only tends to lift the craft and reduce the hull-to-water friction, but the streamlining involved also reduces the air resistance. As shown in Figure 1, the top of the hull is smoothly curved from how to stern, and the bottom also follows the general contour of an airfoil. Shape characteristics of airfoils are well known and need not be described here. The upward curvature of the bottom at the bow is somewhat greater than that of the top so that the boat tends to lift itself out of the water in event the bow is submerged.

The bottom is designed to further reduce the contact between the hull and water surface. As shown in Figure 1, the bottom is stepped at a transverse riser 8 to provide a leading area 9 and an offset trailing area I! disposed above the rear edge of the leading area. In a 70 foot boat having a 20 foot beam the riser 8 is preferably located back about 44 feet from the bow, and is preferably about 8 inches high. This provides a planing angle of about 1 degrees. Another riser i2 is also preferably provided at the stern to further elevate the bottom of tail [3.

Leading area 9 of the bottom is V-shaped, the angle of divergence being quite wide at all points since the boat is essentially'a fiat bottom one. At the bow the V-angle is quite pronounced, as shown in Figure 2, to give a water splitting action, and then gradually widens out to a substantially? flat angle at the rear of the leading area, as illustrated in the section of Figure 3. In order to give stability against side slip, the portions of leading area 9 at the wide angle on opposite sides of the keel line are concave or dished as shown craft. A small fin I4 is also preferably provided on the keel line at riser 8.

Trailing area H is slightly V-shaped, with the angle of divergence also widening from front to rear as shown in Figures 4 and 5. This bottom area is substantially straight longitudinally, and in a 70 foot boat is preferably about 26 feet long.

At full running speed in smooth water my boat contacts the water surface only at the rear por tions of the leading and trailing areas as indicated by the planing angle line H5 in Figure 1.

The amount of hull-to-water contact depends upon the speed of the craft. At a running speed of about 100 M. P. H. I have demonstrated that the craft rides with a barely perceptible water contact on a smooth watersurface, practically the entire body of the boat flying through the air above the water. In rough water where additional upward impetus is given by the water swells, I have traveled as much as 500 feet through the air with only the propellers 'in'the water. Under these conditions the craft travels in a medium of least resistance, namely air; and the propellers work in a heavier medium for best efiiciency, namely water. tially obtained even when there is some hull-towater contact, although under these normal conditions the boat is more accurately described as skimming over the water surface. From the practical standpoint, however, the craft'may be treated as a flying boat, because the water contact is so small that its resistance may be largely disregarded.

In order-to facilitate making turns while steer- 7 ing, the bottom edges of the hull are beveled along both the leading and trailing areas. This beveled edge structure substantially eliminates the possibility of upsetting on sharp turns, even at high speeds. 1

Since my boat travels with little or no water contact, it is very-important'that the propulsion means neutralize its own torque, otherwise it would be impossible to keep a truecourse and there would be grave danger of spinning and upsetting. I therefore use a propulsion unit I I having a pair of coaxial propellers IBrotating in opposite directions. One or more of these units may be provided at the rear edge of trailing area l, two being shown in Figure 6. These are preferably outboard units mounted on stern IS in a Well 2| in the false shell of tail l3. Twin propeller propulsion units of the character described in my Patent No. 2,064,195 are preferably used.

An improved mounting is also provided for the propulsion units. Referring again to Figure 6, each unit carries a hollow semi-spherical ball 22 which seats in an open ended arcuate socket 23 secured to the hull in an aperture 24. The socket is made in two pieces to facilitate assembly and the socket flanges are bolted to'the stem with an interposed gasket 26 to provide a watertight seal. Ball 22 is machined to fit closely'in the socket to effect a watertight closure. If desired, suitable packing rings may be provided inthe socket and the structure filled with a waterproof grease to insure a tight water seal.

Drive connection with the unit is made through aperture 24 and through the'ball and socket joint. Shaft 21 from engine 28 connects with the drive shaft he the unit through a universal joint 29 disposed in hollow ball 22, thus transmitting-driving torque to the unit withoutinterfering with the free pivotal action at the ball and socket joint. The improved mounting thus does two things; first, it-provides a, universal pivot for the oute This ideal is substanboard unit, and second, it provides a watertight seal for the drive shaft through the stern.

Steering is accomplished by turning the propulsion units about their vertical axes. Movement about a vertical axis is stabilized by a loose pin hinge 30 between the unit and hull below the ball and socket joint. See Figure l.

The steering mechanism comprises a trans-.

verse rack 3| on the stern, connected with a steering shaft 32 through a pinion 33. Ends of rack 3| are pivotally connected to the propulsion units by links 34, so that movement of the steering rack simultaneously pivots the units about their vertical axes. Because the axes of the drive shafts pass through the centers of the pivot mountings, the engine torque does not affeet the steering action.

Another feature of the ball and socket mounting is that it enables the propulsion unit to be turned or folded upwardly by merely disconnecting link 34 and pulling the pin of hinge 30. Such upending of the unit, Without dismounting it from the stem, is desirable for servicing or repairing the propeller end. Well 2| in the false tail structure is suficiently large to permit this upward folding movement; and a suitable socket at the top for receiving the loose pin hinge section provides a convenient latch for holding the folded unit. In operation, the well is preferably covered with sliding doors to preserve the continuity of the top surface.

I have amply demonstrated the superior speed qualities of my boat in competitive races. Its usefulness however is not limited to sports. When fitted with torpedo tubes the boat becomes an effective naval weapon, not only because of its high speed and small crew requirement, but also because it is a seaworthy craft capable of carrying a formidable torpedo load.

I claim:

1. A boat comprising a hull having a well in its stern portion, an outboard propulsion unit upon the stern below said Well, a ball and socket joint for mounting said unit upon said hull for universal pivotal movement relative thereto, driving means extending to the unit through the ball and socket joint, said driving means including a universal joint concentric with the ball .and socket joint, and stabilizing means including a detachable pivot positioned in vertical alignment with the center of the joints. 7 V 2. A boat comprising a hull, an outboard propulsion-unit, a' ball and socket jointfor mounting the unit on' the hull, one portion of said joint being attached to the hull and the other portion of the joint being attached to the propulsion unit,

- driving means extending from the hull to'the unit 7 upon the stern below the well, a universal joint through'said joint, means for effecting a watertight seal between the ball and the socket, and means including a detachable pivot aligned with the centerof'the ball and socket joint for 'nor-' mally stabilizing the unit against vertical displacement.

' 3; A. boat comprising a hull having a well in its stern portion, an outboard propulsion unit for mounting. the. propulsion unit upon the hull and permitting an upending movement of the propulsion unit within the well, and means in- 

